Date: Tue, 31 Aug 1999 00:34:49 -0400
Reserve Lighting function, (only applicable to some models where compulsory
headlights ON is built in).
The headlight ON is controlled by a relay in the fuse box (junction Box).
Follow the text below in conjunction with h-light.jpg from the VROC picture
library Aug 99.
1. Ignition Switch ON, nothing happens yet,
2. Press Start button, 12 Volts is felt at the Start Relay closing the
contacts (provided there is an earth through either the clutch or neutral
switch).
3. 12 volts is then felt at the start motor Solenoid which then starts the
engine.
4. releasing the start button removes 12 volts from the base of the H/L
relay, and provides an earth (or nearly an earth from the base of the H/L
relay through the Start motor solenoid. (this is a bit weird but hold in
there).
5. Since the engine is now running AC voltage is being produced from the
alternator.
6. Alternator AC volts is half wave rectified through the adjoining diode to
produce a positive pulsing DC.
7. The first positive pulse through the diode energises the H/L relay
closing the contacts.
8. With the contacts closed 12 volts passes through the H/L fuse to the
dipper switch, and via diode to the H/L relay (this is a hold on circuit).
9. Note the hold on circuit is locked ON by its own 12 volts and will not
release until the ignition switch is turned OFF. If the engine stalls or the
kill switch is operated the engine will stop, but lights stay on. So if you
have a week battery switch the ignition off ASAP. During an immediate engine
restart the start, 12 volts will drop out the H/L relay due to 12 volts at
it's base and swamping the earth path.
Drive Safe
Have Vulcan, no therapy required. <<H-LIGHT.jpg>>
Bob Wilson
0733063402
Robert.Wilson@Australia.Boeing.com
H-LIGHT.jpg
